Two unidentified persons on a two-wheeler on Wednesday hurled a 'petrol' bomb at the BJP's district office in Thiruvananthapuram, police said.

No one was in the office when the incident took place.

A chair in front of the office was found in a burnt condition, police said.

BJP district president S Suresh alleged that CPI-M was behind the attack and said the incident happened at about 8.30 pm. He said police came to the spot very late.

Suresh said the party has called for a 12-hour shutdown from 6 am to 6 pm in the district on Thursday.

The attack comes in the backdrop of the attempt to manhandle CPI(M) general secretary Sitaram Yechury in New Delhi by two men who claimed they were members of a group called Hindu Sena.